1. Field of the Invention
This invention relates to the conditioning, that is, to the improvement of one or more properties, of fabrics in a laundry dryer. More particularly, it relates to an improved fabric-conditioning article in the form of a flexible, resilient, polymeric foam substrate that carries one or more conditioning agents, and to methods for its use and manufacture. The fabric-conditioning article is commingled and tumbled with wet or damp fabrics in a laundry dryer, whereby the conditioning agent is transferred to the fabrics while the fabrics are being dried.
2. Prior Art
It has long been known to condition fabrics, especially, but not limited to, fabrics made from synthetic fibers, by the addition of various chemical compositions to the fiber surfaces. Such compositions, or conditioning agents, include lubricating, bacteriostatic, moth-proofing and mildew-proofing agents, and particularly include softening agents and anti-static agents. Conditioning agent compositions frequently comprise mixtures of two or more conditioning agents to accomplish two or more objectives with a single treatment. For example, it is common practice to combine a softener and an anti-static agent into a single fabric conditioning agent.
In laundries, especially in home laundries, an early approach was to add a liquid fabric-conditioner, designed to be substantive to fabrics, to the rinse water during a wash cycle, particularly to the final rinse. Another approach has been to add a fabric-conditioner to the wash water at the beginning of the wash cycle, either separately along with the detergent or as a combination product containing both conditioner and detergent. Neither approach was completely satisfactory due to a number of factors, including the inactivation of cationic fabric-conditioners by small amounts of anionic detergents left in fabrics and in rinse water, inefficient utilization of conditioner, some of which may be incompletely substantive and thus lost down the drain with the rinse water, and unsatisfactory economics because many of the conditioners have limited solubility and are sold as dilute solutions in water or water/alcohol mixtures, which increases packaging and shipping costs. Another negative factor in the case of products added during the rinse cycle is inconvenience, since the housewife must remember to add the fabric-conditioner at the proper stage during the cycle of her otherwise automatic washing machine. To overcome these shortcomings, the art continued to seek more efficient, economical, and convenient ways to package and apply fabric-conditioners especially for use in home laundry appliances.
In U.S. Pat. No. 3,442,692 Gaiser disclosed a method of conditioning fabrics in a heated laundry dryer by tumbling the damp fabrics in contact with a flexible substrate carrying a conditioning agent. Illustratively, the flexible substrate is paper or cloth, which has been thoroughly impregnated with a conditioning agent. In a later related patent, U.S. Pat. No. 3,895,128, Gaiser disclosed a fabric conditioning article comprising a web having a discrete surface coating of a normally-solid fabric softener. Illustratively, the web is a fibrous material such as paper.
In U.S. Pat. No. 3,632,396, Perez-Zamora disclosed a fabric-softening composition consisting essentially of a paper, woven cloth, or nonwoven cloth substrate coated first with a waxy substrate coating to prevent the outer coating from penetrating and becoming entrapped in the substrate, and then coated with an outer coating of a fabric softener.
Hewitt et al, in U.S. Pat. No. 3,676,199, disclosed a method of conditioning by tumbling the damp laundry in contact with an article comprising a form-retaining, or rigid, base with a surface coating of a conditioning agent. The base is, illustratively, a polystyrene foam ball, or a piece of wood, rock, expanded metal, or other foamed plastic.
In U.S. Pat. No. 3,686,025, Morton disclosed a fabric softening composition consisting essentially of a fabric softener impregnated into an absorbent substrate having a defined absorbent capacity and being an adhesively-bonded nonwoven cloth. The disclosure stresses that impregnation, or permeation of the entire substrate structure, rather than coating, is essential in order to avoid staining of fabrics. In a divisional patent, U.S. Pat. No. 3,843,395, Morton disclosed a process for softening freshly washed fabrics in a heated automatic clothes dryer by tumbling the fabrics in contact with the composition of U.S. Pat. No. 3,686,025.
In U.S. Pat. No. 3,870,145, Mizuno disclosed a multi-use reusable article comprising a sponge completely impregnated with a fabric conditioner, which is attached to the wall of a machine dryer.
In U.S. Pat. No. 3,936,538, Marshall et al disclosed a fabric softening composition consisting essentially of a self-supporting pre-formed film comprising a film-forming polymer, a fabric softener, and a waxy surfactant. Also disclosed is a process for softening freshly washed fabrics in a rotary drum clothes dryer comprising drying the fabrics in contact with the self-supporting film.
In U.S. Pat. No. 3,944,694, McQueary disclosed a fabric-conditioning article comprising a flexible web, illustratively a nonwoven cloth, carrying a fabric-conditioning agent, the substrate containing slit openings to permit the flow of air through the substrate during use. In a divisional patent, U.S. Pat. No. 4,012,540, a method of conditioning fabrics in a laundry dryer by commingling the fabrics with the foregoing fabric-conditioning article is disclosed. McQueary disclosed a similar fabric-conditioning article in U.S. Pat. No. 3,956,556, except that the substrate contains perforations rather than slits. The use of the perforated article for conditioning fabrics in a laundry dryer is disclosed in a divisional patent, U.S. Pat. No. 4,007,300.
In U.S. Pat. No. 4,022,938, Zaki et al disclose a fabric softening article, for use in an automatic laundry dryer, comprising a cationic fabric softener, a sorbitan ester, and a dispensing means which is a flexible substrate in sheet configuration. Preferably, the substrate is a sheet of paper or nonwoven cloth into which the softener and sorbitan ester are impregnated. The dispensing means can also be a cloth or paper bag, or a hollow sponge, enclosing the softening mixture.
Murphy, in U.S. Pat. No. 4,049,858, disclosed a non-staining fabric softening article for use in an automatic clothes dryer comprising a mixture of a sorbitan ester and a water-soluble fatty acid soap in combination with dispensing means. Dispensing means can be a sheet of woven cloth, nonwoven cloth, or paper, and can contain slits or holes; and can also be a hollow, open pore, polyurethane sponge pouch or a cloth or paper bag.
An article for conditioning fibrous materials, comprising a solid base coated on at least one side with a continuous coating of a plasticized nonionic, anionic, or cationic surface active agent was disclosed in U.S. Pat. No. 4,057,673 by Falivene. The solid base is a form-retaining material such as a polystyrene foam ball, wood, a light mineral, or other foamed plastic.